Continuous 11-week feeding of reduced-fat distillers grains with and without monensin reduces lactation performance of dairy cows

Abstract

This study investigated the effects of continuous feeding of high inclusion of reduced-fat corn distillers grains with solubles with and without monensin on dry matter intake (DMI), production, milk fatty acid profile, and plasma AA profile in lactating cows. The experiment was conducted for 12 wk (1-wk covariate, 2-wk diet adaptation, and 9-wk experimental period of data collection) with 36 Holstein cows in a randomized complete block design. Cows were blocked by parity, days in milk, and milk yield and assigned to the following diets: (1) control (CON), (2) CON with reduced-fat corn distillers grains with solubles included at 28.8% (dry matter basis) replacing soybean meal, soyhulls, and supplemental fat (DG), and (3) DG with monensin (Rumensin; Elanco Animal Health, Greenfield, IN) supplemented at a rate of 20 mg/kg of DM offered (DGMon). Orthogonal contrasts were used to compare CON versus DG and DGMon and to compare DG versus DGMon. Milk yield was not affected (40.3 vs. 40.8 kg/d) by DG and DGMon compared with CON. However, for DG and DGMon compared with CON, decreased DMI (24.9 vs. 26.4 kg/d), milk fat yield (1.12 vs. 1.55 kg/d), milk protein yield (1.24 vs. 1.32 kg/d), and energy-corrected milk yield (37.7 vs. 43.5 kg/d) were observed. Feeding DGMon compared with DG did not affect DMI (24.4 vs. 25.4 kg/d) and milk yield (39.2 vs. 41.3 kg/d) but decreased milk fat yield (1.08 vs. 1.23 kg/d), milk protein yield (1.20 vs. 1.28 kg/d), and energy-corrected milk yield (36.0 vs. 39.4 kg/d). Interactions between treatment and week for DMI, milk fat yield, and energy-corrected milk indicate that production responses to DG and DGMon versus CON were decreased over the experimental period. Cows fed DG and DGMon had increased milk fat concentration of trans-10,cis-12 18:2, trans-10 18:1, and long-chain (>16C) and polyunsaturated fatty acids and decreased short-chain (<16C) and odd- and branched-chain fatty acids compared with CON. No difference was observed between DG and DGMon in milk fatty acid profile. In the current study, feeding a high-DG diet did not sustain DMI and production, and supplementing monensin to a high-DG diet further decreased DMI and production.

Validating intrinsic markers and optimizing spot sampling frequency to estimate fecal outputs

“…However, in growing bulls fed grass-based diets, DM digestibility estimated using iNDF differed from TC and was dependent on the pore size of the incubation bag used (Huhtanen et al, 1994). Since then, bags with a pore size of 25 µm have been widely used (Lee et al, 2012;Morris et al, 2018;Velásquez et al, 2018), and our study confirmed that iNDF with the 25-µm incubation bags accurately estimated fecal outputs and apparent digestibility of DM, OM, and N compared with TC. When comparing AIA and TC, Lee and Hristov (2013) reported an underestimation of fecal output of approximately 15%.…”

Effects of corn feeding reduced-fat distillers grains with or without monensin on nitrogen, phosphorus, and sulfur utilization and excretion in dairy cows

“…The experiment was carried out at the Ohio Agricultural Research and Development Dairy Center (Wooster, OH). Information about animals, experimental design, and dietary treatments were described in de-tail in our previous study (Morris et al, 2018). Briefly, 36 (9 primiparous and 27 multiparous) Holstein cows (average ± SD at the beginning of the trial: milk yield = 44.2 ± 8.1 kg/d; DIM = 80 ± 31 d; BW = 675 ± 74 kg) were blocked into groups of 3 (n = 12) by parity, DIM, and milk yield.…”

“…Although this resulted in a decrease in dietary Ca content in the DG diets (Table 1), Ca supply exceeded NRC (2001) requirements. Further information about dietary composition is available in our previous study (Morris et al, 2018). The experiment consisted of a diet adaptation period for 2 wk and a 9-wk experimental period (wk 1 through 9 refers to the 9-wk experimental period).…”

Effects of a high-protein corn product compared with soy and canola protein sources on nutrient digestibility and production responses in mid-lactation dairy cows

“…In the case of Hubbard et al (2009), a high-protein corn product increased milk and FCM yields, and a high-protein distillers grain corn product decreased milk protein concentration in another case (Kelzer et al, 2009). Reduced-fat distillers grains maintained (Castillo-Lopez et al, 2014;Morris et al, 2018) or increased milk yield (Ramirez-Ramirez et al, 2016) but decreased 3.5% FCM, fat, and protein yields in a more recent study (Morris et al, 2018). Cows fed a diet with corn gluten meal as the primary protein source, compared with soybean meal, produced similar quantities of milk and FCM but produced less milk protein in early lactation (Wohlt et al, 1991).…”

“…The fermentation process results in spent grains known as distillers grains with solubles (DGS), which have a CP concentration of 27 to 31% (Belyea et al, 2004;Liu, 2011). Removal of fat from DGS marginally increases CP concentration (34%; Wang et al, 2007;Morris et al, 2018), and removal of bran and germ components enhances the efficiency of ethanol production and increases CP concentration to more than 40% (Corredor et al, 2006;Robinson et al, 2008). Distillers grains have successfully been fed to beef (Klopfenstein et al, 2008) and dairy cattle (Kelzer et al, 2009;Schingoethe et al, 2009) as a protein source, and the inclusion has become more common as ethanol production grows.…”